Pure carotenoid crystals derived from Marigold flowers, comprising predominantly of Xanthophylls such as Lutein, Zeaxanthin and Cryptoxanthin and low levels of carotene have been proven scientifically to reduce the risk of age related macular degeneration (Reference: Moeller S M, Jacques P F, Blumberg J B “The potential role of dietary Xanthophylls in cataract and age related macular degeneration,” Journal of the American College of Nutrition, 2000; 19:522S-527S), control over LDL cholesterol (Reference: Chopra M., Thumham D I, “Effect of Lutein on oxidation of low density lipoproteins (LDL) in vitro”, Proceedings of the Nutrition Society, 1994; 53: 1993, #18A), prevention of Coronary heart diseases (Reference: Howard A N, Williams N R, Palmer C R, Cambou J P, Evans A E, Foote J W, et al., “Do hydroxy-carotenoids prevent coronary heart disease?” A comparison between Belfast and Toulouse, “International Journal of Vitamin and Nutrition Research, 1996; 66: 113-118) and free radicals scavenging and immunity enhancing (Reference: Chew B P, Wong M W, Wong T S, “Effects of Lutein from Marigold extract on immunity and growth of mammary tumors in mice,” Anticancer Research, 1996; 16: 3689-3694).
Lutein, (β-ε-carotene-3-3-diol) and Zeaxanthin (β-β-carotene-3-3′-diol) belong to Xanthophylis group in the carotenoids family with highly reactive hydroxyl groups which cannot be synthesized by humans and animals.
Carotenoids are a class of natural fat-soluble pigments found principally in plants, algae, and photosynthetic bacteria, where they play a critical role in the photosynthetic process. They also occur in some non-photosynthetic bacteria, yeasts, and molds, where they may carry out a protective function against damage by light and oxygen. Although animals appear to be incapable of synthesizing carotenoids, many animals incorporate carotenoids from their diet. Within animals, carotenoids provide bright coloration, serve as antioxidants, and can be a source for vitamin A activity (Ong and Tee 1992; Britton et al. 1995).
Carotenoids are responsible for many of the red, orange, and yellow hues of plant leaves, fruits, and flowers, as well as the colors of some birds, insects, fish, and crustaceans. Some familiar examples of carotenoid coloration are the oranges of carrots and citrus fruits, the reds of peppers and tomatoes, and the pinks of flamingoes and salmon (Pfander 1992). Some 600 different carotenoids are known to occur naturally (Ong and Tee 1992), and new carotenolds continue to be identified (Mercadante 1999).
Carotenoids are defined by their chemical structure. The majority carotenoids are derived from a 40-carbon polyene chain, which could be considered the backbone of the molecule. This chain may be terminated by cyclic end-groups (rings) and may be complemented with oxygen-containing functional groups. The hydrocarbon carotenoids are known as carotenes, while oxygenated derivatives of these hydrocarbons are known as xanthophylls. Beta-carotene, the principal carotenoid in carrots, is a familiar carotene, while Lutein, the major yellow pigment of marigold petals, is a common xanthophyll.
The structure of a carotenoid ultimately determines what potential biological function(s) that pigment may have. The distinctive pattern of alternating single and double bonds in the polyene backbone of carotenoids is what allows them to absorb excess energy from other molecules, while the nature of the specific end groups on carotenoids may influence their polarity.
The former may account for the antioxidant properties of biological carotenoids, while the latter may explain the differences in the ways that individual carotenoids interact with biological membranes (Britton 1995).
U.S. Pat. No. 5,382,714 reports that saponified marigold oleoresin from Kemin Industries (Des Moines, Iowa) containing free lutein is the preferred starting material for the isolation of pure lutein. The saponification step involves high percentage of propylene glycol and the saponification time is done for a minimum period of three hours subjecting the product to heat for prolonged period, which increases the process time too.
U.S. Pat. No. 5,648,564 uses aqueous alkali and propylene glycol wherein the Carotenoid esters are neither soluble nor freely miscible with them and hence it requires very long time at higher temperature for the fatty esters to saponify which may result in exposure of the product for a longer duration under heat and air, promoting the formation of oxidative degenerative products and the process time is too long for a commercial batch.
U.S. Pat. No. 6,743,953 describes final purification step involving multiple solvents like ethyl acetate, hexane, acetone and methanol with the possibilities of leaving residues of the same. Again the process involves saponification upto 3 hrs. Subjecting the product to heat at 70° C. for more time which may result in degenerated oxidative products in the saponified mass.
U.S. Pat. No. 6,380,442 states that the hydrolysis of carotenoids is done by using iso propyl alcohol with saponification time being 90 minutes.
U.S. Pat. No. 6,504,067 states that the Marigold oleoresin is pre treated with Sodium Carbonate and further neutralisation with dilute Phosphoric acid, prior to taking it to saponification reaction using aqueous alkali and carried out the saponification at a temperature at 90° C. for 8 hours. Subsequently the reaction mass is subjected to readjustment of pH with acetic acid to 5.0, and washing the residues with excess water in order to bring the pH to neutral. The disadvantage in the process is that the product is subjected to heat for a prolonged period and too many steps of acidification and neutralisations are involved to remove the impurities.